The invention relates to a valve to shut off or control a fluid stream, with a housing exhibiting one inlet and one outlet each for the fluid stream to be controlled, a control member disposed between the inlet and outlet, and an actuating element for the control member.
Especially in recent years valves have been known that allow, for example, a control member for a fluid stream to be influenced in accordance with an applied voltage while utilizing the inverse piezo effect. The inverse piezo effect has the advantage of being able to make do with only a small amount of electric energy in order to actuate the control member, but is accompanied by the drawback that only relatively small deformations or adjusting paths are possible. In order to take this circumstance into consideration, either lever transmissions or the like are to be provided, in order to increase sufficiently the range of change in the cross sections to be controlled--a feature that makes the valves complicated and susceptible--or the valve is to be designed and applied from the beginning only as a pilot valve for small cross sections or fluid mass flow. Similar advantages and disadvantages are also to be expected, for example, when actuating the control member by means of other suitable actuating elements, which utilize the thermal expansion (bimetals or the like) or the socalled shape memory (memory metals).
The object of the present invention is to design a valve of the aforementioned kind in such a manner that while retaining the advantages of the simple actuation or control, the aforementioned drawbacks are avoided and that also a relatively large fluid mass flow can be controlled with minimum complexity in design.